Skip to main content
Fig. 1 | Avian Research

Fig. 1

From: Maternal effects, malaria infections and the badge size of the house sparrow

Fig. 1

Model describing the hypotheses investigated in this study. Numbers in the figures correspond to processes hypothesized to take place: 1. High prenatal testosterone exposure, which increases digit ratio has been shown to reduce immunocompetence and hence increases the risk of being infected by malaria, 2. at the same time birds with higher digit ratios have been shown to have a larger badge size, 3. spraying insecticide reduces vector abundance which in turn has a negative impact on malaria prevalence in a population. The opposite is true in unsprayed, natural areas, and 4. malaria in turn may affect badge size through trade-offs due to the effects of the parasite or by provoking an immune response

Back to article page